class Unionfind {
public:
    vector<int> data;
    Unionfind(size_t size) : data(size, -1) { }
    bool connect(size_t x, size_t y) {
        x = root(x); y = root(y);
        if (x != y) {
            if (data[y] < data[x]) swap(x, y);
            data[x] += data[y]; data[y] = (int)x;
        }
        return x != y;
    }
    inline bool same(size_t x, size_t y) {
        return root(x) == root(y);
    }
    inline size_t root(size_t x) {
        return (size_t)(data[x] < 0 ? x : data[x] = root(data[x]));
    }
    inline int size(size_t x) {
        return -data[root(x)];
    }
};

int H,W;
{
    rd(H,W);
    Unionfind uf(H*W+1);
    register int cnt;cnt = H*W+1;
    int p = 0;
    REP(y, H){
        REP(x, W){
            int c;rd(c);
            if (c == 0) cnt -= uf.connect(p, H*W);
            else{
                if (0<y && !uf.same(p-W, H*W)) cnt -= uf.connect(p, p-W);
                if (0<x && !uf.same(p-1, H*W)) cnt -= uf.connect(p, p-1);
            }
            ++p;
        }
    }
    wt(cnt-1);
}